1. Field of the Invention
The invention relates to a fender structure for bicycles and particularly to a fender structure that is installable by users and adaptable to various sizes of the bicycles, and adjustable in shape, length, color and angle, and foldable and detachable, and is simple to assemble and install, and has a great versatility and applicability.
2. Description of the Prior Art
A conventional fender 71 (referring to FIG. 1) generally is made in an integrated plate which has a front section fastened to a stretcher 73 located on an upper side of the rear fork 72 of the bicycle 7 through a fastening plate 711 and a rear section fastened to a bracket 74 through a coupling blade 712. Such a structure is plainly designed and cannot be altered to suit the desire and requirements of individual. Moreover, it has the following drawbacks:                1. Different types and models of bicycles require different specifications of fenders. They are often not compatible. Hence producers have to prepare and stock many specifications of fenders to meet production requirements.        2. The conventional fenders are generally integrally made. When they are not in use and removal from the bicycle is wanted, they take a lot of space. Carrying and storage are inconvenient.        
To remedy these problems, some venders have developed an extendable fender 8 as shown in FIGS. 2 and 3. While the extendable fender 8 can resolve the problems occurred to the conventional fenders, it still has shortcomings, notably:                1. The fender 8 has an arched plate 81 which has latch stubs 811 slidable in flutes 812 of another arched plate 81. The arched plates 81 do not have anchor structure. Thus the arched plates 81 tend to retract under vibration when the bicycle is ridden.        2. When the fender 8 is not in use and retracted, the arched plates 81 tend to slide out during riding.        3. When the fender 8 is retracted, the distal ends of the arched plates 81 are generally aligned to the tail end of a box 80. The arched plates 81 do not have gripping means for pulling out when in use. Pulling out operation takes a lot of efforts and is not convenient.        4. Such type of fender usually is made in a single specification, and cannot be adapted to bicycles of different specifications or wheels of different sizes. Moreover, the angle of the fender is not adjustable. It has limited applicability, and cannot be adapted universally.        